Acoustical building construction



March 13, 1934. R. H. STITT ACOUSTICALBUILDING CONSTRUCTION Filed April 9, 1931 INVENTOR RO EQHST/ 7'71 ATTORNEY UNITED STATES PATENT OFFICE 1,950,420 ACOUSTICAL BUILDING CONSTRUCTION Roger H. Stitt, Chicago, Ill., assignor to United States Gypsum Company, Chicago, 111., a cor- This invention poration of Illinois Application April 9, 1931, Serial No. 528,797

' 8 Claims. (01. 72 1s) relates to building constructions,

and has reference more particularly to building constructions in which building surfaces are faced with acoustical sound absorbing tile for correcting the acoustical properties of a room.

It is common practice to correct the acoustics in a room by applying acoustical tile to the walls and ceiling thereof. These tiles are usually composed of a base of fibrous material, such as mineral wool, vegetable fiber, etc., or they may be composed of a porous, ceramic material containing a multitude of inter-connectedpores for absorbing the sound waves.

These tiles are usually applied to the building surface by means of an adhesive material which is spread upon the backs of the tiles only around the perimeter thereof, so as to permit a limited amount of contraction and expansion in the center of the tile. This method of application leaves a space between the ceiling surface and the back face of the tile, and some difiiculty has been experienced with the passage of air through the pores of the tile into this space, commonly known as breathing". The continuous ebbing of air through the tile, carries with the air current dust, dirt, smoke and other impurities, which serve to eventually soil the outer surface of the tile and render the room unsightly in appearance. Furthermore,

Reference is t o be had to the accompanying drawing, forming a part of this specification, in

which Fig. 1 is a perspectiveview of one of the acoustical tiles,

Fig. 2 is a secti onal view through a wall or ceiling construction, showing one form of attachment for the acoustical tiles,

Fig. 3 is a sectional view through a wall or ceiling construction plication of the showing a modified form of apimpervious coating to the back surface of the acoustical tiles,

Fig. 4 is a sectional view through another form of construction, showing another form of attaching the tiles to the ceiling or walls,

Fig. 5 is a perspective view of an acoustical tile for use with the construction shown in Figure 4, and

Fig. 6 is a sectional view through a wall or celling construction showing a further modified form of tile attaching means.

The wall or ceiling surface 10 may consist of a layer of plaster mounted upon metal lath, wood lath, plasterboard or other suitable material. '60 Acoustical tiles 11 are attached to the ceiling surface 10, these tiles usually consisting of a fibrous material, such as mineral wool with suitable binding agents. The edges 12 of the tiles are usually bevelled to present a pleasing architectural effect. 5 The tiles 11 are preferably positioned in edge to edge abutting relation, being secured to the wall surface 10 around the edges of each tile by an adhesive material 13 of asphalt emulsion, or other cementing agents such as plaster of Paris with suitable modifying ingredients. The layer of cementing adhesive 13 spaces the tile 11 apart from the ceiling surface 10 so as to usually form a space 14, and as previously pointed out, there is a tendency for air to breathe through the 7 tiles, ebbing to and from from the space 14, and carrying dirt into the pores of the tile.

The salient feature of the present invention consists in applying to the back surface of the tile, a layer of material 15, which is substantially g non-porous and is impervious to the passage of air. This layer 15 may also consist of a plastic material, such as asphalt emulsion, percipitated cellulose, lacquer, paint, etc., the main property being its lack of porosity so as to prevent the passage of air through the tile. The layer 15, preferably extends only across the central area of the tile 11, leaving the outer edges 16 on the back surface of the tile uncovered so as to directly receive the tile attaching adhesive material 13. In this way there is a direct bond between the body of the tile and the wall surface 10 through the attaching adhesive material 13, thus avoiding any loosening of the tile from the ceiling or wall surface, due to contraction and expansion of the tile with change in temperature of theroom. However, the paper layer 15 may cover the entire back surface of the tile as shown in Fig. 3, so that the tile is attached to the ceiling surface through the paper layer. This form of construction shown in Fig. 3 is not as desirable as that shown in Fig. 2, because it is necessary to use a stronger and more expensive adhesive between the paper and the body of the tile 11 to prevent the paper from tearing loose adjacent the attaching adhesive 13 due to expansion and contraction of the tiles. In order to permit the use of a weaker and cheaper adhesive between the paper sheet 15 and the tile body 11, it is pomible to form inclined slots no 19 in the back face of the tile, these slots following the edges of the tile at a substantial distance therefrom. These slots may be formed by milling cutters or by other suitable planing tools. When such a tile as shown in Fig. 5 is applied to the ceiling surface as shown in Fig. 4, the adhesive attaching material 13 extends downwardly into the slots 19 to form locking keys 20 which contact directly with the body of the tile and prevent any loosening of the tile due to contraction and expansion thereof. If desired, dove-tailed slots 21 as seen in Fig. 6 may be formed around the rear outer perimeter of the tile. The construction shown in Fig. 6 has the advantage that there is a smaller danger of breakage of the edge of the tile adjacent the slots 21 than there is adjacent the slots 19. The construction shown in Fig. 6 provides a very firm attachment between the tiles and the ceiling surface 10 through the adhesive material 13, because of the very positive key 22 formed in the registering dove-tailed slots 21.

I would state in conclusion that while the illustrated examples constitute practical embodiments of my invention, I do not wish to limit myself precisely to these details, since'manifestly, the same may be considerably varied without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, I claim' as new and desire to secure by Letters Patent:

1. An acoustical tile comprising a porous material having connected porosity from the front face to the rear face thereof, a layer of material attached tothe rear face of said tile, said material being substantially impervious to the passage of air, said tile having keying slots formed in the rear face thereof for the reception of attaching adhesive material.

2. In a building construction, a wall or ceiling sin-face, acoustical tiles in spaced, parallel relation to said building surface, adhesive plastic means for attaching said tiles to said building surface around the perimeter of said tiles, and a layer of material impervious to the passage of air and attached to the rear face of said tile, said layer being spaced apart from the edges of said .tile.

3. In a building construction, a building surface, acoustical tiles in spaced, parallel relation to said building surface, a layer of material impervious to the passage \of air and =adhesively attached to the rear face of said tile, said layer extending over a portion only of rear face of said tile so as to expose the outer back edges of said tile, and adhesive cementing material connecting said exposed edges of said tile to said building surface.

4. In a building construction, a building surface, acoustical tiles in spaced, parallel relation to said building surface, the edges of said tile being in abutting relation one to the other, dovetailed registering slots formed around the rear back edge of each tile, and adhesive cementing material engaging in said slots and attaching said tiles to said building surface.

5. In a. building construction, a building surface, acoustical tiles in spaced, parallel relation to said building surface, said tiles having a connected porosity from the front to rear face thereof, a layer of material secured to the rear face of said tile, said material being substantially impervious to the passage of air, said tile having keying slots formed on the rear face thereof, said slots passing through saidlayer into the body of 'the tile and spaced apart from the edge of the tile, and plastic cementing material engaging in said slots and adhering to said building surface so as to attach said tiles to said building surface.

6. In a building construction, a wall or ceiling member, porous acoustical tiles of relatively fragile'structure in substantially parallel relationship adjacent said member, a layer of material substantially impervious to the passage of air attached to the rear face of said tiles and adapted to prevent breathing through said tiles, portions at the back edges of said tiles being uncovered by said material, and means in engagement with said uncovered portions and serving to connect said tiles to said member.

7. In a building construction, a wall or ceiling member, porous acoustical tiles of relatively fragile structure in substantially parallel relation adjacent said member, a. thin layer of material of different properties than said tiles ,adhesively secured to the rear face of said tiles, and means engaging portions of said tiles which are not covered by said material and which are at an angle to the rear face of said tiles for connecting said tiles to said member.

8. An acoustical tile comprising a porous material having substantially connected porosity from the front face to the rear face thereof, and a layer of material substantially impervious to the passage of air and attached to the rear face of said tile, said layer extending over a portion only of the rear face of said tile and leaving substantial portions of said rear face exposed for engagement by means for connecting said tile to a supporting surface in a building.

ROGER H. STITT. 

